add iterative summing in chapter 6

Author: mariofusco

src/main/java/lambdasinaction/chap5/Summarizing.java

@@ -30,7 +30,7 @@ private static Dish findMostCaloricDish() {
     }
 
     private static Dish findMostCaloricDishUsingComparator() {
-        Comparator<Dish> dishCaloriesComparator = Comparator.comparing(Dish::getCalories);
+        Comparator<Dish> dishCaloriesComparator = Comparator.comparingInt(Dish::getCalories);
         BinaryOperator<Dish> moreCaloricOf = BinaryOperator.maxBy(dishCaloriesComparator);
         return menu.stream().collect(reducing(moreCaloricOf)).get();
     }

src/main/java/lambdasinaction/chap6/ParallelStreams.java

@@ -4,7 +4,15 @@
 
 public class ParallelStreams {
 
-    public static long sum(long n) {
+    public static long iterativeSum(long n) {
+        long result = 0;
+        for (long i = 0; i < n; i++) {
+            result += i;
+        }
+        return result;
+    }
+
+    public static long sequentialSum(long n) {
         return Stream.iterate(1L, i -> i + 1).limit(n).reduce(Long::sum).get();
     }
 

src/main/java/lambdasinaction/chap6/ParallelStreamsHarness.java

@@ -8,7 +8,8 @@ public class ParallelStreamsHarness {
     public static final ForkJoinPool FORK_JOIN_POOL = new ForkJoinPool();
 
     public static void main(String[] args) {
-        System.out.println("Sum done in: " + measurePerf(ParallelStreams::sum, 10_000_000L) + " msecs");
+        System.out.println("Iterative Sum done in: " + measurePerf(ParallelStreams::sequentialSum, 10_000_000L) + " msecs");
+        System.out.println("Sequential Sum done in: " + measurePerf(ParallelStreams::sequentialSum, 10_000_000L) + " msecs");
         System.out.println("Parallel forkJoinSum done in: " + measurePerf(ParallelStreams::parallelSum, 10_000_000L) + " msecs" );
         System.out.println("Range forkJoinSum done in: " + measurePerf(ParallelStreams::rangedSum, 10_000_000L) + " msecs");
         System.out.println("Parallel range forkJoinSum done in: " + measurePerf(ParallelStreams::parallelRangedSum, 10_000_000L) + " msecs" );

src/main/java/lambdasinaction/chap6/WordCount.java

@@ -32,7 +32,7 @@ public static int countWordsIteratively(String s) {
 
     public static int countWords(String s) {
         //Stream<Character> stream = IntStream.range(0, s.length())
-        //                                    .mapToObj(i -> SENTENCE.charAt(i)).parallel();
+        //                                    .mapToObj(SENTENCE::charAt).parallel();
         Spliterator<Character> spliterator = new WordCounterSpliterator(s);
         Stream<Character> stream = StreamSupport.stream(spliterator, true);
 
@@ -41,8 +41,8 @@ public static int countWords(String s) {
 
     private static int countWords(Stream<Character> stream) {
         WordCounter wordCounter = stream.reduce(new WordCounter(0, true),
-                WordCounter::accumulate,
-                WordCounter::combine);
+                                                WordCounter::accumulate,
+                                                WordCounter::combine);
         return wordCounter.getCounter();
     }